MEMS can include numerous electromechanical devices fabricated on a single substrate, many of which are to be separately actuated in order to achieve a desired operation. For example, a MEMS optical switch may include numerous mirrors that are each positionable in a desired orientation for reflecting optical signals between originating and target locations upon actuation of one or more microactuators associated with each mirror. In order for each mirror to be separately positioned, separate control signals need to be supplied to the microactuators associated with each mirror. One manner of accomplishing this is to connect each microactuator to a control signal source with a separate electrical conductor (i.e., an interconnect line) fabricated on the surface of the substrate that extends between its associated microactuator and a bond pad at the periphery of the substrate where it can be easily connected to an off-chip control signal source. In this regard, since there are numerous interconnect lines, there are typically numerous bond pads arranged in close proximity to each other along the periphery of the substrate.
In fabricating the multiple bond pads it may be desirable to employ a blanket metalization process step wherein the entire region of the substrate where the bond pads are located is covered with gold or another highly conductive material rather than trying to employ a shadow mask that restricts application of the metal to only the surfaces of the individual bond pads. However, such blanket metalization has the drawback that it may lead to short circuit conditions. For example, if the interconnect lines are electrically isolated from each other by overlying shield structures, the shield structures cannot contact the bond pads and thus must end prior to the bond pads thereby exposing the interconnect lines for a short distance in the gaps between the bond pads and the ends of the shield structures. Thus, if blanket metalization is employed, the exposed portions of the interconnect lines may receive undesired metalization leading to short circuits between individual interconnect lines and their associated shield structures or between adjacent interconnect lines. Furthermore, even if blanket metalization is not employed, slight misalignment of an appropriately configured shadow mask can also result in undesired metalization of the exposed portions of the interconnect lines.